udev/udevadm-settle.c

   1 /*
   2  * Copyright (C) 2006-2008 Kay Sievers <kay@vrfy.org>
   3  *
   4  * This program is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include <stdlib.h>
  19 #include <stddef.h>
  20 #include <string.h>
  21 #include <stdio.h>
  22 #include <unistd.h>
  23 #include <errno.h>
  24 #include <dirent.h>
  25 #include <fcntl.h>
  26 #include <syslog.h>
  27 #include <getopt.h>
  28 #include <sys/stat.h>
  29 #include <sys/types.h>
  30
  31 #include "udev.h"
  32
  33 #define DEFAULT_TIMEOUT                 180
  34 #define LOOP_PER_SECOND                 20
  35
  36 static void print_queue(struct udev *udev, const char *dir)
  37 {
  38         LIST_HEAD(files);
  39         struct name_entry *item;
  40
  41         if (add_matching_files(udev, &files, dir, NULL) < 0)
  42                 return;
  43
  44         printf("\n\nAfter the udevadm settle timeout, the events queue contains:\n\n");
  45
  46         list_for_each_entry(item, &files, node) {
  47                 char target[NAME_SIZE];
  48                 size_t len;
  49                 const char *filename = strrchr(item->name, '/');
  50
  51                 if (filename == NULL)
  52                         continue;
  53                 filename++;
  54                 if (*filename == '\0')
  55                         continue;
  56
  57                 len = readlink(item->name, target, sizeof(target));
  58                 if (len < 0)
  59                         continue;
  60                 target[len] = '\0';
  61
  62                 printf("%s: %s\n", filename, target);
  63         }
  64
  65         printf("\n\n");
  66 }
  67
  68 int udevadm_settle(struct udev *udev, int argc, char *argv[])
  69 {
  70         char queuename[PATH_SIZE];
  71         char filename[PATH_SIZE];
  72         unsigned long long seq_kernel;
  73         unsigned long long seq_udev;
  74         char seqnum[32];
  75         int fd;
  76         ssize_t len;
  77         int timeout = DEFAULT_TIMEOUT;
  78         int loop;
  79         static const struct option options[] = {
  80                 { "timeout", 1, NULL, 't' },
  81                 { "help", 0, NULL, 'h' },
  82                 {}
  83         };
  84         int option;
  85         int rc = 1;
  86         int seconds;
  87
  88         dbg(udev, "version %s\n", VERSION);
  89
  90         while (1) {
  91                 option = getopt_long(argc, argv, "t:h", options, NULL);
  92                 if (option == -1)
  93                         break;
  94
  95                 switch (option) {
  96                 case 't':
  97                         seconds = atoi(optarg);
  98                         if (seconds > 0)
  99                                 timeout = seconds;
 100                         else
 101                                 fprintf(stderr, "invalid timeout value\n");
 102                         dbg(udev, "timeout=%i\n", timeout);
 103                         break;
 104                 case 'h':
 105                         printf("Usage: udevadm settle [--help] [--timeout=<seconds>]\n\n");
 106                         goto exit;
 107                 }
 108         }
 109
 110         strlcpy(queuename, udev_get_dev_path(udev), sizeof(queuename));
 111         strlcat(queuename, "/.udev/queue", sizeof(queuename));
 112
 113         loop = timeout * LOOP_PER_SECOND;
 114         while (loop--) {
 115                 /* wait for events in queue to finish */
 116                 while (loop--) {
 117                         struct stat statbuf;
 118
 119                         if (stat(queuename, &statbuf) < 0) {
 120                                 info(udev, "queue is empty\n");
 121                                 break;
 122                         }
 123                         usleep(1000 * 1000 / LOOP_PER_SECOND);
 124                 }
 125                 if (loop <= 0) {
 126                         info(udev, "timeout waiting for queue\n");
 127                         print_queue(udev, queuename);
 128                         goto exit;
 129                 }
 130
 131                 /* read current udev seqnum */
 132                 strlcpy(filename, udev_get_dev_path(udev), sizeof(filename));
 133                 strlcat(filename, "/.udev/uevent_seqnum", sizeof(filename));
 134                 fd = open(filename, O_RDONLY);
 135                 if (fd < 0)
 136                         goto exit;
 137                 len = read(fd, seqnum, sizeof(seqnum)-1);
 138                 close(fd);
 139                 if (len <= 0)
 140                         goto exit;
 141                 seqnum[len] = '\0';
 142                 seq_udev = strtoull(seqnum, NULL, 10);
 143                 info(udev, "udev seqnum = %llu\n", seq_udev);
 144
 145                 /* read current kernel seqnum */
 146                 strlcpy(filename, udev_get_sys_path(udev), sizeof(filename));
 147                 strlcat(filename, "/kernel/uevent_seqnum", sizeof(filename));
 148                 fd = open(filename, O_RDONLY);
 149                 if (fd < 0)
 150                         goto exit;
 151                 len = read(fd, seqnum, sizeof(seqnum)-1);
 152                 close(fd);
 153                 if (len <= 0)
 154                         goto exit;
 155                 seqnum[len] = '\0';
 156                 seq_kernel = strtoull(seqnum, NULL, 10);
 157                 info(udev, "kernel seqnum = %llu\n", seq_kernel);
 158
 159                 /* make sure all kernel events have arrived in the queue */
 160                 if (seq_udev >= seq_kernel) {
 161                         info(udev, "queue is empty and no pending events left\n");
 162                         rc = 0;
 163                         goto exit;
 164                 }
 165                 usleep(1000 * 1000 / LOOP_PER_SECOND);
 166                 info(udev, "queue is empty, but events still pending\n");
 167         }
 168
 169 exit:
 170         return rc;
 171 }